Cons:
- Requires a lot of protection
- Rely on silver bolt
- Short range
- Needs to position well
- Hard to master

Summoner's spell

Flash: Great for escape and can be used for potentially outplaying the opponent.
Barrier: Great for baiting.
Cleanse: If the enemy has a lot of crowd control.
Heal: Better for a support to take.
Ghost: Gives a lot of mobility.
Ignite: For Securing kills.

Runes

Life steal runes: Better Sustain in lane
Flat AD runes: Good for trading
Armor Penetration: Good for dealing raw damage
Armor Runes: Absorbs quite a bit of damage, good for trading.
Magic resist runes: Good against other ADC such as Kog'Maw and AP Supports